#include <iostream>
#include <math.h>
using namespace std;

#define PI 3.1415926

int main(int argc, const char *argv[])
{
    double in_x, out_y;

    while (1) {
        cin >> in_x;
        out_y = sin(in_x+PI*2);
        cout << out_y << endl;
    }

    return 0;
}
